Pharmocology (MQC)

Question 1

What is pharmacodynamics ?

Answer 1

What the drug does to the body

Question 2

What is pharmacokinetics ?

Answer 2

What the body does to the drug

Question 3

What are the 4 stages of the body processing a drug ?

Answer 3

Absorption
Distribution
Metabolism
Excretion

Question 4

Describe and explain the “absorption” process in the body

Answer 4

This process in the body is how the drug makes it way into the blood circulation. This can be done by oral intake, some of the drug will be absorbed by the lining of the stomach, but most of it will be absorbed by the small intestine. When the drug is absorbed it will then be taken to the liver by the “hepatic portal vein”

Question 5

What is “ first pass metabolism” ?

Answer 5

This is when the liver metabolises some of the drug before it can get to the systemic circulation, this is what is known as “ first pass metabolism”
This can impact the amount of the drug that is able to be used by the body

Question 6

Routes of medications that bypass “ first pass metabolism” ?

Answer 6

Inhaled
Rectal
Intravenous/subcutanious/intramuscular
Transdermal
Buccal (in the gum)

Question 7

List some factors that may effect absorption of medications

Answer 7

Food and other types of medications - can bind with foods, medications can also bind with each other reducing the ability to work within the body

Erratic coating - helped the medication to not be absorbed by the GI tract and activates later

Controlled release drugs - modified drugs so that they are released over a longer period of time/slower

Question 8

Explain the process of distribution with drugs in the body

Answer 8

This is the dispersion of the drug throughout the different fluids and tissues within the body. Drugs don’t distribute evenly throughout the body and also have different outcomes for different drug types (water or lipid soluble drugs)
The drugs penetrate the body’s tissues at differing speeds and also can depend on their ability to pass over the cells membranes.

Question 9

What is the Blood Brain Barrier (BBB)

Answer 9

This is a selective semipermeable membrane that acts as a wall between the nervous system and the brain from the blood supply.
This helps to stop toxins and pathogens from getting to the central nervous system.

Question 10

Which drugs can pass the Blood brain barrier (BBB)

Answer 10

The more lipid soluble a drug is, the more likely it is to be able to pass the BBB

Question 11

What happens when drugs bind to plasma proteins ?

Answer 11

When they circulate the blood steam a percetage of the drug will bind with the plasma proteins, some of the drug will still roam free within the circulating blood unbound.
This unbound pieces of the drug are small enough to leave the capillaries and enter the interstitial fluid surrounding the cells and work its effects on the body
Bound portion too big to leave capillaries - none effective

Question 12

Explain and describe the process of metabolism of drugs in the body

Answer 12

The primary site for metabolism is within the liver, but also along the GI mucosa and lungs
The main purpose of metabolism is to turn the drug into a more water soluble so it can be excreted by the kidneys, into the urine

Question 13

Explain the two phases of drug metabolism

Answer 13

1. Carried out in the liver by enzymes called “Cytochrome P450 enzymes” which oxidise drugs
2. A big ionised molecule added to the drug to make it more water soluble

Question 14

Describe and explain the process of excretion of drugs

Answer 14

This is the body’s way of removing the drug from its systems. Which is primarily done by the kidneys into urine output

Drugs can also be excreted by other methods too, bile, stool, breast milk and tears

Question 15

What is bioavailability ?

Answer 15

The amount of each drug that makes its way to the systemic circulation.
This differs for all medications, due to absorption in the GI tract
IV said to have the best bioavailability at 100%

Question 16

What is the narrow therapeutic range ?

Answer 16

The difference between the blood levels required for a drugs desired therapeutic range, and what levels the drugs are toxic

Question 17

What is the plasma half-life ?

Answer 17

The time it intakes for a concentration of the drug plasma to reduce by half - indicates how long a drug lasts in the body for

Question 18

The three ways the drugs cause their effects on the body ?

Answer 18

Binding to cell receptors

Acting on enzymes

Acting on transporters

Question 19

What is an Antagonist ?

Answer 19

Drug that binds to cell receptors and block the agonists, preventing or reducing cell receptors

Question 20

What is an Agonist ?

Answer 20

Binds to cell receptors and activated/stimulates a cellular response

Question 21

How do enzyme inhibitors work ?

Answer 21

These drugs bind to the enzyme and decrease the activity in the body
Enzymes promote biochemical reactions within the body

Question 22

Explain the effects of drugs acting on transporters

Answer 22

Transporters are proteins found in the cells membrane that filtrate substances into and out of the cell
Drugs acting on theses transporters can increase or decrease the process of transportation in and out depending on the drug

Question 23

What are chemotherapeutic drugs ?

Answer 23

They work by interfering with the cell growth and division of cells and bacteria
Chemotherapy - cancer treatment
Antibiotics - attract bacterial cell wall, inhibiting synthesis

Question 24

What is polypharmacy ?

Answer 24

This is when a person is presecribed many medications at one time for multiple morobidities

Question 25

Explain why polypharmacy might be problematic ?

Answer 25

This can be due to the prescription of multiple drugs interacting with each other inappropriately, this can cause harm rather than than good for the body
Potential drug interactions may occur if not followed up with patients. Medicine management is advised for the best use of all the drugs within the patients system